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a(n) = (2*n+1)*denominator((2*n+1)*Bernoulli(2*n)).
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%I #14 Jul 31 2021 20:14:01

%S 1,6,30,42,90,66,2730,30,510,798,2310,138,13650,54,870,14322,5610,210,

%T 1919190,78,13530,1806,2070,282,324870,1122,1590,43890,16530,354,

%U 56786730,126,6630,64722,690,4686,140100870,150,2310,3318,6210270,498,57873270,174

%N a(n) = (2*n+1)*denominator((2*n+1)*Bernoulli(2*n)).

%H Robert Israel, <a href="/A326580/b326580.txt">Table of n, a(n) for n = 0..10000</a>

%F a(n) = A326579(2*n + 1).

%p A326580 := n -> (2*n+1)*denom((2*n+1)*bernoulli(2*n)):

%p seq(A326580(n), n=0..43);

%t Table[(2n+1)Denominator[(2n+1)BernoulliB[2n]],{n,0,50}] (* _Harvey P. Dale_, Jul 31 2021 *)

%o (PARI) a(n) = (2*n+1)*denominator((2*n+1)*bernfrac(2*n)); \\ _Michel Marcus_, Jul 19 2019

%Y Cf. A326579, A326578, A326478, A027641/A027642 (Bernoulli).

%K nonn

%O 0,2

%A _Peter Luschny_, Jul 17 2019